One of the most promising classes of candidate materials for high temperature composite and adhesive applications has been the aromatic imide compositions. In particular, the six-membered imide system has demonstrated excellent thermooxidative properties and resistance to hydrolysis from environmental moisture.
Unfortunately, the imide systems are formed by condensation reactions with the evolution of volatile by-products. In the fabrication of reinforced composite structures, the volatile by-products, which are evolved, form voids which greatly weaken the structures. There is a real need, therefore, for an imide composition which possesses all the required fabrication criteria while having the capability of being converted to a thermally stable, high molecular weight polymer by a non-volatile addition reaction. Furthermore, the most attractive six-membered imide system has not been utilized as a composite or adhesive material because of its inability to form a high molecular weight polymer by the normal condensation process.
It is a principal object of this invention, therefore, to provide ethynyl-substituted aromatic `peri` anhydrides which can be used as endcapping agents in the synthesis of imide compositions, thereby enabling such systems to cure by addition reactions.
Another object of the invention is to provide new and improved bis-ethynyl `peri`imide compositions which polymerize via addition reactions.
A further object of the invention is to provide a method for synthesizing the endcapping agents.
Other objects and advantages of the invention will become apparent to those skilled in the art upon consideration of the accompanying disclosure.